Amazon is getting into comics and graphic novels publishing – both physical and digital – with the launch of an imprint called Jet City Comics.

The imprint already has some high-profile authors and illustrators signed up, including Game of Thrones writer George R.R. Martin, whose short story Meathouse Man is being adapted into a graphic novel for release in October 2013.

Amazon will also release new digital editions of the out-of-print graphic novels based on Martin's stories The Hedge Knight and The Sworn Sword in November 2013 and early 2014 respectively.

Science fiction author Neal Stephenson and Hugh Howey are also on board, with the latter's series of Wool short stories is already a notable self-publishing success through Amazon's Kindle ebooks store.

Amazon says that Jet City Comics books will be released digitally through its Kindle store in standalone and serialised form, but also published as print editions. It's the company's latest venture into publishing its own book as well as selling those from other publishers.

"Comics and graphic novels, especially in digital format, represent a unique area for innovation," said Amazon Publishing vice president Jeff Belle in a statement.

"Our focus will be on adapting great books for this medium as a means of expanding the audience for our authors, pushing boundaries with new ideas that combine visual and narrative storytelling, and creating compelling new experiences for readers."

Now Amazon will be competing with DC Comics, Marvel Comics and other publishers as well as selling their products – a tightrope the company is already walking with its existing digital and physical imprints.

Jet City Comics is just the latest digital disruption for the comics and graphic novels industry. Its announcement came as Marvel released one digital-only series – Wolverine: Japan's Most Wanted – and announced another, Iron Man: Fatal Frontier.

Both are being released as part of Marvel's Infinite Comics digital-only imprint, which was announced in March 2012 as "a new technique in comics storytelling that is built specifically for the digital world yet in a very elegant way manages to keep the purity of what makes a comic a 'comic,'".

Marvel has since launched Marvel Unlimited, a subscription service for digital comics that costs $9.99 a month or $69 a year, offering unlimited access to the company's archives and new issues online, or on iOS and Android devices.

Meanwhile, companies like ComiXology are striking deals with publishers to sell digital editions of their comics. The company reached 100m downloads through its web, iOS, Android and Kindle Fire apps in October 2012, and now sells more than 35k comics from more than 75 publishers.

ComiXology is also now selling subscription-based access to its catalogue, as well as offering bundles of "curated collections" of comics through its apps, including some of Marvel's most famous series.